U.S. patent number 6,692,469 [Application Number 09/463,748] was granted by the patent office on 2004-02-17 for injection devices.
This patent grant is currently assigned to Ares-Trading S.A.. Invention is credited to Steven Mark Guy Rolfe, Stuart Weekes.
United States Patent |
6,692,469 |
Weekes , et al. |
February 17, 2004 |
Injection devices
Abstract
An injection device has a barrel (1) for housing and guiding a
syringe (13) as it is urged forward to project its needle (14),
while the dose is ejected, and as a return spring (22) retracts it.
A firing mechanism (6) is connectable to the rear end of the barrel
and is re-usable, whereas the barrel (1) with its spent syringe
(13) is disposable. The connection (4) has limited freedom of axial
movement so that, once made, forward pressure on the firing
mechanism (6) moves the syringe (13) up to a ready position. A
number of barrels (1) with syringes (13) can be housed in a common
box (31) with a single firing mechanism (6), the forward end of
each barrel (1) being screwed to a locator (32) on the base of the
box. The engagement of the firing mechanism (16) with the rear end
of each barrel (1) is also screw-threaded, but of opposite hand, so
that screwing the firing mechanism (6) on and continuing to turn
releases the complete device; and correspondingly the barrel (1)
can be returned and located in the box (31) while the firing
mechanism (6) is separated from it.
Inventors: |
Weekes; Stuart (Oxford,
GB), Rolfe; Steven Mark Guy (Oxon, GB) |
Assignee: |
Ares-Trading S.A. (Vaumarcus,
CH)
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Family
ID: |
10816687 |
Appl.
No.: |
09/463,748 |
Filed: |
January 31, 2000 |
PCT
Filed: |
July 30, 1998 |
PCT No.: |
PCT/GB98/02287 |
PCT
Pub. No.: |
WO99/06100 |
PCT
Pub. Date: |
February 11, 1999 |
Foreign Application Priority Data
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Jul 31, 1997 [GB] |
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9716065 |
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Current U.S.
Class: |
604/197; 604/137;
604/157; 604/187 |
Current CPC
Class: |
A61M
5/002 (20130101); A61M 5/2033 (20130101); A61M
5/3205 (20130101); A61M 5/008 (20130101); A61M
5/3204 (20130101); A61M 5/326 (20130101); A61M
5/46 (20130101); A61M 2005/206 (20130101) |
Current International
Class: |
A61M
5/20 (20060101); A61M 5/00 (20060101); A61M
5/32 (20060101); A61M 5/46 (20060101); A61M
005/32 () |
Field of
Search: |
;604/181,187,196,218,220,228,232,240,257,186,117,134,135,136,137,110,198,197 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 666 084 |
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Aug 1995 |
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EP |
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2 623 403 |
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May 1989 |
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FR |
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2 654 938 |
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May 1991 |
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FR |
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WO 88/06463 |
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Sep 1988 |
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WO |
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WO 95/31235 |
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Nov 1995 |
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WO |
|
Primary Examiner: Dawson; Glenn K.
Assistant Examiner: Maynard; Jennifer
Attorney, Agent or Firm: Young & Thompson
Claims
What is claimed is:
1. An injection device formed as two separate assemblies, the first
assembly comprising a barrel having forward and rear ends, a
syringe carrier for a syringe with a needle within the barrel
axially movable between a rearward position, in which the needle of
the syringe carried thereby is retracted within the forward end of
the barrel, and a forward position, in which the needle projects
from the forward end of the barrel, spring means urging the carrier
towards the rearward position, and a connector, and the second
assembly comprising a firing mechanism with a firing member which,
when released, acts on the syringe to urge the syringe forwards to
said forward position and then to eject a dose, wherein the firing
mechanism is separable from the barrel and in that the connector
has limited freedom of axial movement at the rear end of the barrel
and is configured for attachment of the firing mechanism, the
connector initially being held at a rearward position by the spring
means acting through the syringe carrier, but moving to a forward
position, taking the syringe carrier with it, as the barrel is held
against the skin by the firing mechanism being pressed forwards,
the syringe carrier then being in a position intermediate said
forward and rearward positions of said syringe carrier from which
said syringe carrier can be propelled to said forward position of
said syringe carrier on actuation of the firing mechanism, and the
connector reverting under the influence of the spring means to said
rearward position after removal of the injection device from the
skin.
2. An injection device as claimed in claim 1, characterised in that
the attachment is by mating screw threads, the connector being
restrained against rotation with respect to the barrel.
3. An injection device as claimed in claim 1, characterised in that
the connector is a stepped tube creating a smaller diameter
portion, at a rear end thereof and a larger diameter portion at a
forward end thereof, the smaller diameter portion at the rear end
providing a socket to receive the firing member the stepping in the
tube defining an internal forward facing shoulder providing an
abutment for a rear end of the syringe carrier, and the stepping in
the tube also defining an external, rearward facing shoulder
providing an abutment for engagement with a locking ring, fitted to
the rear end of the barrel, when the connector is at its rearward
position.
4. An injection device as claimed in claim 3, characterised in that
the syringe carrier has a lost-motion connection with the
connector, this defining the limit of the carrier's forward
movement.
5. An injection device as claimed in claim 4, characterised in that
the larger diameter portion of the stepped tube connector has
axially parallel slots in which projections from the rear end of
the syringe carrier engage to form the lost-motion connection.
6. An injection device as claimed in claim 1, characterised in that
the barrel is internally equipped with guide means, having forward
and rear ends, for keeping the syringe carrier co-axial
therewith.
7. An injection device as claimed in claim 6, characterised in that
the spring means is a coil spring having forward and rear ends and
surrounding the syringe carrier to engage a flange at said rear end
and reacting against an abutment within the barrel.
8. An injection device as claimed in claim 7, characterised in that
the abutment is provided by the rear end of the guide means.
9. An injection device as claimed in claim 1, characterised in that
the forward end of the barrel is equipped with means for
effectively altering the barrel length and thus the amount by which
the needle of the syringe will project.
Description
FIELD OF THE INVENTION
This invention relates to injection devices.
BACKGROUND OF THE INVENTION
After any injection, the syringe with its needle is thrown away
into a guarded enclosure, for obvious safety reasons. But removing
it from a re-usable device that first fires the syringe forwards to
make the needle penetrate, then pushes the syringe piston forwards
to eject the dose, and which finally withdraws the syringe and
needle, can itself be hazardous and time-consuming.
One answer is to discard everything, but such injection devices are
complex and expensive. That is not therefore a realistic
option.
However, by making the device in two parts, one being a re-usable
firing mechanism with a plunger that can be released to spring
forwards, and the other being a housing and guide for the syringe
to which the firing mechanism can be temporarily attached, it
becomes possible to contemplate throwing away this other part
(still containing a syringe).
It is the aim of this invention to provide such a device.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided
an injection device comprising a barrel, a syringe carrier within
the barrel axially movable between a rearward position, in which
the needle of a syringe carried thereby is retracted within the
forward end of the barrel, and a forward position, in which the
needle projects from the forward end of the barrel, spring means
urging the carrier towards the rearward position, and a firing
mechanism with a firing member which, when released, acts on the
piston in the syringe to urge the syringe forwards and then to
eject a dose, characterised in that the firing mechanism is
separable from the barrel and in that there is a connector with
limited freedom of axial movement at the rear end of the barrel for
attachment of the firing mechanism, the connector initially being
held at a rearward position by the spring means acting through the
syringe carrier, but moving to a forward position, taking the
syringe carrier with it, as the barrel is held against the skin by
the firing device being pressed forwards, the syringe carrier then
being in an intermediate position from which it can be propelled to
its forward position on actuation of the firing mechanism, and the
connector reverting under the influence of the spring means to its
rearward position after removal of the injection device from the
skin.
The spring means will act through the carrier, the syringe, the
firing member and its device to cause the reversion of the
connector to its rearward position.
Conveniently, the attachment is by mating screw threads, the
connector being restrained against rotation with respect to the
barrel.
The connector may be a stepped tube, the smaller diameter portion
at the rear end providing a socket to receive the firing device,
the internal forward facing shoulder formed by the step providing
an abutment for the rear end of the syringe carrier, and the
external, rearward facing shoulder formed by the step providing an
abutment for engagement with a locking ring, fitted to the rear end
of the barrel, when the connector is at its rearward position.
The syringe carrier may have a lost-motion connection with the
connector, and this will define the limit of the carrier's forward
movement. The larger diameter portion of the stepped tube connector
may have axially parallel slots in which projections from the rear
end of the syringe carrier engage to form the lost-motion
connection.
The barrel will generally be internally equipped with guide means
for keeping the syringe carrier co-axial therewith.
The spring means is conveniently a coil spring surrounding the
syringe carrier to engage a flange at the rear end thereof and
reacting against an abutment within the barrel. This abutment may
be provided by the rear end of the guide means.
Preferably, the forward end of the barrel is equipped with means
for effectively altering its length and thus the amount by which
the needle of the syringe will project.
According to another aspect of the present invention there is
provided injection equipment comprising a plurality of disposable
syringe devices which have retracted needles in the pre-use and
post-use conditions, a firing mechanism which can be screw-fitted
to the rear end of each device, and a housing for said devices, the
leading ends of each syringe device being screw-threadedly
engageable with locators in the housing, these screw threads being
of opposite hand to that of the firing mechanism whereby, for use
of a syringe device located in the housing, the firing mechanism is
screwed to its rear end and the screw action continued until the
syringe device releases from its locator, and post-use the syringe
device is screwed back on its locator using the firing mechanism
and the screw action continued until the firing mechanism releases
from the syringe device.
Preferably each pre-use syringe device has a rear end cap removable
to allow screw attachment of the firing mechanism.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention one embodiment will now
be described, by way of example, with reference to the accompanying
drawings, in which:
FIG. 1 is an axial section of an injection device as supplied,
without any firing mechanism.
FIG. 2 is an axial section of the device with the firing mechanism
fitted, and ready for use,
FIG. 3 is a detail, in perspective, of part of the injection
device,
FIG. 4 is an axial section of the device, with its firing
mechanism, during injection,
FIG. 5 is an axial section of the device, with its firing
mechanism, after use, and
FIG. 6 is a cutaway perspective view of a housing for is a set of
injection devices.
DETAILED DESCRIPTION OF THE INVENTION
An injection device has a barrel 1 with a tapered forward part 2
and a generally cylindrical rearward part 3. Telescoped into this
rearward part 3 and prevented from rotating by a splined engagement
(not fully shown) there is stepped connector tube 4 whose lesser
diameter rear end provides a socket 5 into which a firing mechanism
6 is screwed. This is of a known kind having a trigger button 7 at
its rear end which, when pressed, causes a plunger 8 to project
from its forward end. It also has a window 9 through which can be
seen marks indicating whether it has been fired or not. The tube 4
is made captive to the barrel 1 by a snap-in locking ring 10 which
sleeves between the part 3 and the socket 5 and engages the barrel
1 by a circumferential rib and groove arrangement 11 and a shoulder
12. The ring 10 is therefore effectively integral with the barrel
1, and its forward end provides an annular shoulder against which
the external step in the tube 4 normally abuts, preventing escape
of that tube.
Within the barrel 1 there is a syringe comprising a capsule 13 with
a needle 14 at its forward end, initially shielded by a needle cap
15. The capsule is enclosed over most of its length by a sleeve 16,
which has an outwardly projecting flange 17 at its rear end
initially abutting the internal step of the tube 4. This forms a
syringe carrier. As seen in FIG. 3, this carrier has a lost-motion
connection within the connector 4, whose large diameter forward end
18 has longitudinal slots 19 in which lugs 20 projecting from the
flange 17 engage. An anti-rotation spline 21 can also be seen in
FIG. 3. A coil spring 22 surrounds the sleeve 16, its rear end,
within the connector 4, engaging the flange 17 and its forward end
abutting internal shoulders 23 provided by the rear ends of
fin-like guides 24 within the tapered portion 2 which keep the
syringe aligned during injection. Initially this spring 22 is
unstressed.
Fitted around the forward end of the part 2 there is a nose piece.
25, which is smoothly rounded comfortably to abut the user's skin
and which can be adjusted to lengthen and shorten the barrel and
thereby alter the depth of needle penetration.
In the initial state, a tubular insert 26 projects into the tapered
part 2 beyond the needle cap 15, where it has an inturned rim 27
engaging behind the enlarged base of the cap 15. Outside the
forward end of the barrel 1 the insert can be grasped by a flange
28. Within the mouth of the forward part 2 of the barrel there are
studs 29 which co-operate with screw-threading 30 on the exterior
of the insert 26. This is of coarse pitch and of opposite hand to
the screw-threading in the socket 5.
For use, the firing mechanism 6 is screwed into the socket 5 and
the complete injection assembly is parted from the insert 26 which
pulls the cap 15 off the needle .14. Because of the opposite hand
threads, screwing away the insert 26 does not undo the fixing
mechanism 6 for the socket 5.
The injector is then applied to the skin of the user, and the
firing device 6 urged forward. This carries the tube 4 forwards,
telescoping further into the rear part 3 of the barrel 1, which of
course is held static by its engagement with the patient. This
movement continues until the connector 4 is arrested, conveniently
by the anti-rotation spline(s) 21 meeting the end(s)of the
associated groove(s) in the barrel. During this movement, the
spring 22 is partially compressed and the syringe is also carried
forwards, but the needle 14 is not quite projected beyond the nose
piece 25.
The button 7 is then pressed and the plunger 8 shoots forward
engaging the piston (not shown) in the capsule, first projecting
the capsule, with its carrier 16, forwards and causing the needle
to pierce the skin. The carrier is stopped by the lugs 20 meeting
the forward ends of the slots 19, but the plunger 8 carries on to
eject the dose (FIG. 4).
Finally, the injector is withdrawn, and the spring 22 exerts
itself. During the injection, it has been fully compressed, but now
it re-expands, urging the capsule carrier 16 rearwardly, and taking
with it the capsule, thereby withdrawing the needle safely within
the barrel. At the same time, through the plunger 8, the whole
firing mechanism 6 is shifted rearwardly with the connector 4,
until the outer step in the connector 4 engages the ring 10 (FIG.
5).
The firing mechanism 6 is then separated from the injection device,
and the latter can be thrown away while the firing mechanism is
reusable.
The insert 26 may be a separate item as shown in FIG. 1, or it
could be one of several fixed to and upstanding from the bottom of
a case 31 as shown in FIG. 6, each insert (now referenced 32) being
fitted with an injection device as shown in previous Figures. The
barrels 1 are upright and their cylindrical portions 3 locate in
tubular guides 33 depending from an apertured, horizontal partition
34. The locking rings 10 are just below the partition and so the
devices are not readily accessible. A single firing mechanism 6
which can be fitted to each injection device in turn is also
supplied within the case and located by the partition 34.
When such a device is to be used, a cap 35 covering the socket 5
and proud of the partition 34 is removed and thrown away, and the
firing mechanism 6 is taken out, entered through the aperture in
the partition, and screwed into the socket. When it reaches its
fully mated position, the user carries on turning in the same
direction and this rotates the barrel 1. The studs 29 are forced up
the screw-threading 30 to lift the injection device until it is
free to be drawn clear of the case 31.
After use, the injection device is replaced, being turned by the
firing mechanism 6 to screw down onto the insert 32. When it is
fully on, continued turning screws the firing mechanism 6 free of
the socket 5. The empty socket (not re-covered by the throwaway
cap) indicates that the syringe of that injection device is
spent.
* * * * *